Are kilowatts (kW) and kilowatt hours (kWh) the same? The answer is no. While kW and kWh are related, they are quite different. In this guide, we’ll explain the difference between kW and kWh, what they measure, and why it’s important to understand the difference between them.
What is a kW (kilowatt)?
A kilowatt (kW) or kilowatt is a unit of measurement for the power of an electrical device or load. The higher the kilowattage of a device, the more power it requires to operate.1 kilowatt is equal to 1,000 watts (W).
What is a kWh?
Kilowatt-hour (kWh) is essentially a unit of electrical energy consumed by electrical appliances over time. Its calculation logic can be broken down into: electrical appliance power (unit kW) * operating time (unit h) = electrical energy consumption. Simply put, the greater the power of the device and the longer it is used, the higher its cumulative energy consumption (kWh) must be.
Take two typical devices as examples:
Low energy consumption scenario: A 65-inch LED TV (power 100W=0.1kW) is a low-power device. It will accumulate 1kWh of energy consumption after running for 10 hours, which is equivalent to an average family watching 3 hours a day for more than three days;
High energy consumption scenario: As a high-power device, a 60kW DC fast charging pile can complete 1kWh of electrical energy transmission in just 1 minute, which is equivalent to replenishing about 6-8 kilometers of battery life for electric vehicles per minute (based on the power consumption of mainstream models of 15kWh/100 kilometers).
The Difference Between kW and kWh
Kilowatts and kilowatt-hours are easy to confuse because they are both related units of measurement. The important difference between kW and kWh is what they measure. The kilowatt measures power, which is the rate at which something uses electricity, while the kilowatt hour measures energy, which is the total amount of electricity used or the capacity used.
To truly understand the difference between kilowatts and kilowatt-hours, you also need to consider time. Kilowatt-hours are used to measure the amount of energy used by an electrical device or load in kilowatt-hours. For example, if a 22-kilowatt car charger is used to charge an electric car for one hour, 22 kilowatt-hours of energy will be consumed.
The formula for calculating kWh is (kilowatts x hours = kilowatt-hours). You can see the relationship between kilowatts and kilowatt-hours or power and energy below. In these examples, we show the power (in kilowatts) of the Level 2 (7.5 kilowatts) and Level 3 (60 kilowatts) electric vehicle charging stations on the left.
The kilowatts show the rate at which these electrical devices consume power. On the right, you will see the amount of energy consumed by these EV charging stations over a specified period (2 hours in this case). Based on the kWh formula (kW x hour = kWh), we can calculate the total energy consumed (7.5 kW x 2 hours = 15 kWh). Let’s quickly summarize kW and kWh.
In the field of electric vehicles, kilowatt hour (kWh) denotes the size or capacity of the battery, while kilowatt (kW) denotes the power used to charge the battery. The usage time of a KEHN electric vehicle charger in kW determines the amount of energy consumed by the charger and the amount of energy transferred to the electric vehicle battery in kWh.